1. Field of the Invention
The present invention relates to an engine generator comprising an engine and a generator driven by the engine, in particular, to an engine generator including the engine, the generator, a muffler, or the like within a housing.
2. Description of the Related Prior Art
Conventionally, as an electric power source for use in an out-door condition such as a road repairing work, an out-door shop or an out-door leisure, there has been in use so called an engine generator comprising an engine and a generator driven by the engine, both of which are included in a housing so as to produce an electric power. In fact, such an engine generator is so constructed that a rotor equipped with several pieces of magnets is fixed on a crank shaft in such a manner that the rotor can rotate in the vicinity of a stator equipped with a plurality of coils, thereby generating the electric power.
The Japanese Patent Application Laid-Open No. 11-36879 discloses an engine generator which is provided with countermeasure of sound insulation and thermal insulation. In the system of the above-mentioned publication, the engine and the generator are included within a sound insulation case, six surfaces of which are formed by an under frame, a center cover, a lid member, a front cover, and a rear cover. The sound insulation case is divided into three rooms of front, center and rear ones by two frames of front and rear ones. The rear frame is provided with a through hole, where a duct is mounted passing through the center room and the rear room. Thus, the duct includes the generator, the engine and the muffler, which results in a double sound insulation structure.
Outside the duct of the center room, a fuel tank and intake air devises are arranged. Inside the front room, an electronic equipment is disposed. Furthermore, a pair of right and left reinforcement members are formed across between each upper portion of the front frame and the rear frame. The fuel tank is mounted and fixed between the reinforcement members.
Thus, in the engine generator of the aforementioned publication, the double sound insulation structure is formed by including the generator, the engine, and the muffler, all of which causes working sound, into the duct. In addition, the engine generator disposes high temperature generation equipment, fuel equipment, and electronic equipment therein, separating with each other. In such a way, each equipment is effectively disposed from a viewpoint of countermeasure of sound and thermal insulation in the engine generator, which results in a compact size of the whole device.
However, the aforementioned engine generator has such problems as an inside structure thereof is complicated and the number of parts is increased since the inside of the device is completely divided into three rooms. In addition, the second problem is that an effect of the sound insulation is insufficient since the sound insulation structure including the engine, and the like comprises a simple double structure of the duct made of glass wool and the sound insulation case. Furthermore, since the sound insulation case is constructed by so many parts, i.e. such five parts as a front cover, and others, an outer structure thereof is complicated. Thus, there has been a problem that not only an assembling work at a stage of manufacturing but also a disassembling/reassembling work at a stage of inspection are complicated, and so the number of working steps is increased. Incidentally, since there is need to remove a plurality of covers at a stage of daily inspection also as well as one of an overhaul work, many working steps are essential even when a simple inspection is carried out. Therefore, an improvement of workability thereof has been requested.
In view of the foregoing, an object of the present invention is to provide an engine generator having an enough sturdiness and rigidity, improving a sound insulation performance thereof, and simplifying a structure through reducing the number of parts so as to improve workability at a stage of inspection.
To achieve the foregoing objects, a first aspect of an engine generator according to the present invention is characterized in that an engine generator having an engine, a generator driven by the engine, a muffler disposed at an exhaust side of the engine on a base, and a housing for including the engine, the generator, and the muffler, comprises a partition plate vertically mounted between the engine and the muffler within the housing, a side plate vertically mounted along an end of the housing, a beam mounted across between an upper portion of the side plate and the partition plate, an engine room for including the engine and the generator, said room being surrounded by the base, the partition plate, the side plate, and the beam, and a muffler room surrounded by the base, the partition plate, and the housing for including the muffler.
According to the present invention, the engine room can be formed by cube type frames which are constructed based on the base, the side wall, the partition plate and the beam member. Therefore, the sound insulation preformance of the engine room can be improved due to an existence of the side plate and the partition plate, while the engine room can be constituted with a tough structure due to an existence of the beam member. Thus, even when the housing is made of synthetic resin, the strength of the engine generator can be ensured, thereby improving the vibration isolation performance and durability thereof.
A second aspect of the engine generator according to the present invention is characterized in that in an engine generator having an engine and a generator driven by the engine on a base, and a housing including an upper surface and four side walls for including the engine and the generator, the housing comprises a side cover for integrally forming the base with two adjacent surfaces of the four side walls, a main cover for integrally forming the upper surface with another surface of the four side walls, and a door cover formed by one remaining surface of all the side walls.
In such a configuration, since the housing of the engine generator comprises three parts having each different function such as an overhaul work and a daily inspection, extra parts can be eliminated, and component cost and the number of manufacturing steps can be reduced. Furthermore, it is sufficient for carrying out an adequate inspection within the device that just a door cover may be removed at a stage of daily inspection, and just a main cover at a stage of an overhaul work, and so an unnecessary cover need not be removed, thereby improving workability of the inspection.
The housing may further comprises an outer wall forming an exterior of the engine generator, an inner wall surrounding the engine room and the muffler room, wherein the exterior of the engine generator has a double wall structure formed by the outer and inner walls. Thereby, the engine is surrounded by the housing having the double wall structure, so that the improvement of sound insulation performance can be accomplished. In particular, the portion where the side plate is disposed results in a triple walls structure, thereby obtaining more sound insulation performance.
The housing may be formed by a blow forming of a synthetic resin. Hereby, the hollow double wall structure can be easily formed, so that heat resistance is improved.
In addition, the hollow space of the double wall structure may have foam material filled into, hereby further improving sound insulation performance thereof.